RBG-24818, Forwards Rev 0 to Preservice Insp Request for Relief R0012D Re Bottom Head to Reactor Vessel Circumferential Weld Aa. Exam of Bottom Head Side of Weld Could Not Provide Meaningful Info

Forwards Rev 0 to Preservice Insp Request for Relief R0012D Re Bottom Head to Reactor Vessel Circumferential Weld Aa. Exam of Bottom Head Side of Weld Could Not Provide Meaningful Info

ML20214F989
Person / Time
Site:	River Bend
Issue date:	11/19/1986
From:	Booker J GULF STATES UTILITIES CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
RBG-24818, NUDOCS 8611250514
Download: ML20214F989 (6)

Text

GULF STATES UTELETIES COMPANY RIVER SE ND St ATION POST Of FICE 80X 220 ST FRANCISvtLLE. LOUIStANA 70775 ARE A CODE 604 635 6094 346 8661 I s i

November 19, 1986 l

, RBC- 24818 j File No. G9.5 i Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 i

Dear Mr. Denton:

i River Bend Station - Unit 1 Docket No. 50-458 l As requested by your Staff, Gulf States Utilities (GSU) is

, providing herein supplemental information to a Preservice

} Information Request for Relief R0012D provided in a letter from j J. E. Booker to 11. R. Denton dated May 12, 1986 (RBG-23665).

I Provided in Enclosure 1 to this letter is the revised relief request R0012D.

! The component is the bottom head to reactor vessel

! circumferential weld (Weld AA as shown in Figure D-2) . The

! bottom head to reactor vessel weld requires a volumetric (ultrasonic) preservice examination in accordance with ASME I

Section XI, IWB-2500-1, Examination Category B-B, Item Bl.2.

This inspection requires examinations from both sides of the

) weld.

j During the preservice inspection, a manual ultrasonic examination i was performed from the vessel shell side. All of the required

} adjacent base metal on the shell side of weld AA (upper 1/2T) and essentially 100 percent of weld AA itself were examined.

l Additionally, approximately 50 percent of the adjacent base metal l on the bottom head side of weld AA (lower 1/2T) was examined.

J In obtaining information from the bottom head side below weld AA, a transducer would need to be placed between weld AA and the vessel skirt. Weld AA is located at the edge of a bevel or i transition in vessel diameter as shown in Figure D-2. This is a j relatively small area that has a total length of approximately 6 j inches at an angle of 23 degrees. The surface area is irregular

due to hand grinding and presents a pitch and roll profile along i the slope transition. Additionally, the reactor vessel has a l designed 218 inch inside diameter and a vessel thickness of

! approximately 6 inches which contributes to the inadequacy to perform a lower head ultrasonic scan. Each of these factors l

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Mr. Denton November 19, 1986 contribute to false geometric information that could be given in determining specific location of any reflector. Examination to the bottom head side of the weld (lower 1/2T) could not provide meaningful information and thus, in accordance with ASME Section XI, this relief request was submitted for your review.

Sincerely, J. E. Booker Manager-River Bend Oversight River Bend Nuclear Group Enclosure 1sct JEB/ ERG /JEP/je

t REVISICH 00 PRESERVICE INdmanCN R0012D DATE _ 03/13/86 REQUEST FCR RELIEF CCMPCNDft: Bottcm head to reactor vessel ciremferential weld AA, code category B-B.

CCDE: 'Ihe bottcm head to reactor vessel weld AA was fabricated in accordance with ASME Section III Class 1 requirments. Preservice inspections were performed in accordance with ASME Section XI 1974 Edition through and including Sumer 1975 Addenda.

CCDE REQUIRDOTIS ASME SECTICN XI: Bottcm head to reactor vessel weld AA is required to be volumetric (ultrasonic) irwed for preservice inspection in accordance with ASME Section XI, IWB-2500-1, examination category B-B, Itan Bl.2.

IhTORMATICH 'IO SUPPORT 'INE DETER-MINATICN 'INAT 'INE CCDE RB2UIPDENT ,

reactor vessel CANNOT BE MEra .The bottcm head to circumferential weld AA is located at the edge of a bevel or transition in vessel diameter (see attached figure). 'Ihe gemetry is such that it could be examined frm only the vessel side of the weld as shown in Figure D-1.

REASCN WHY RIiIEF SHOUID BE GPANIID: (1) Weld has been volumetrically exarrd.ned by radiography and hydrostatically tested, found acceptable in accordance with A9tE Section III Class 1 requirements.

(2) Preservice ultrasonic inspection coverage for weld AA is shown in Figure D-1. All of the required adjacent base metal on the shell side of the weld and essentially 100%

of the weld itself were examined by 45 and g

60 angle beams normal to the weld.

Approximately 50% of the adjacent base metal on the bottcm hagd side gf the weld was examined using 45 and 60 angle beams normal to the weld fra the shell side of '

the weld. 'Iha weld was examined 100% for tra:tsverse reflectors in both directions on the shall side of weld AA. 'Ihere was essentially no coverage for transverse reflectors frm the bottcm head side of thg coverage using 45 weldangtherewasnobeams angle fra the~bottcm head and 60 side of the weld.

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~ +x Bottom llead to Vessel Circumferential Weld AA II PRESERVICE INSPECTION REVISION 00

.g. y REQUEST FOR RELIEF R0012D DATE 03/13/86 Page a of 10 UT DEAM (_ AT VESSEL SURFACE

REVISION 0 PRESERVICE INSPECTION DATE 10-09-86 REQUEST EUR RELIEF R0012D PEASON WHY FELIEF SHOUID BE GPMEED:

(Continued) (3) During preservice inspection, manual ultrasonic examination was performed fr m one side, (vessel shell side). This is required because of surf,ce irregularity, (handgrinding causing pitch and roll profile) in the inmediate weld area and the material transition area below the weld. The weld centerline location (measurment frm tangent of transition) on the vessel shell may vary up to 2 inches along the vessel circumference, (C = 730.42 in.). The pitch and roll profile along the slope transition suppleents the insufficient surface mgasur megt to provide a meaningful ultrasonic (45 and 60 )

examination.

(Refer to Fig. D-2)

Page 8A of 10

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